1. Field of the Invention
The present invention relates to a variable displacement swash plate type compressor, and more particularly, to a variable displacement swash plate type compressor capable of simultaneously improving a tilt angle varying operation of a swash plate and a rotating operation of a lug plate, by improving a connection structure of the lug plate and the swash plate.
2. Description of the Related Art
Generally, an air conditioning apparatus of a vehicle maintains a temperature inside the vehicle lower than an outdoor temperature by using a refrigerant, and includes a compressor, a condenser, and an evaporator to generate a circulation cycle of the refrigerant.
Such a compressor compresses and pumps the refrigerant, and is driven by power of an engine or by a motor.
Meanwhile, a swash plate type compressor is classified into a variable displacement swash plate type compressor, wherein a swash plate having a disk shape varies a tilt angle of the swash plate according to a rotation of a driving shaft driven by a power of an engine, and a fixed swash plate type compressor installed in a fixed state.
The variable displacement swash plate type compressor can perform a precise flow rate control by controlling a feed rate of a piston as a tilt angle of a swash plate is continuously changed according to a change of heat load, and improve riding comfort of a vehicle by preventing a rapid torque change of an engine due to a compressor.
Hereinafter, a structure of a variable displacement swash plate type compressor according to a conventional technology will now be described with reference to FIGS. 1A and 1B.
As shown in FIG. 1A, the variable displacement swash plate type compressor includes a front housing 10a accommodating a cylinder block 20 therein, and a rear housing 10b. 
A plurality of cylinder bores 21 are formed in the cylinder block 20, and a piston 30 moving back and forth in a straight line is inserted into the cylinder bore 21 and is connected to a shoe 55 combined to an outer circumference of a swash plate 50 slantly combined to a driving shaft 40.
Also, a lug plate 60 for rotating the swash plate 50 is fixed to the driving shaft 40.
Accordingly, the lug plate 60 rotating with the driving shaft 40 rotates the swash plate 50, and Piston 30 moves back and forth while a tilt angle of the swash plate 50 is changed, thereby compressing a refrigerant.
However, looking at a connection structure of the lug plate 60 and the swash plate 50 of the variable displacement swash plate type compressor shown in FIG. 1B, a projection 62 externally protruding and having a guiding slope 61 is formed at the lug plate 60 and an arm 52 having a moving roller 51 rolled with respect to the guiding slope 61 is formed at the swash plate 50, wherein the lug plate 60 and the swash plate 50 are connected via making surface contact with between the projection 62 and the arm 52.
Here, since a tilting movement of the swash plate 50, wherein the swash plate 50 repeatedly moves from a maximum tilt angle to a minimum tilt angle, and a rotatory power transmittance for transmitting rotatory power of the lug plate 60 to the arm 52 of the swash plate 50 are simultaneously performed respectively at two sides of the projection 62, the tilting movement and the rotatory power transmittance are not smoothly performed. Therefore, the variable displacement swash plate type compressor is easily damaged due to a crack caused by durability deterioration according to a load concentrated in the projection 62.